Objectives of the proposed research are to study electrophysiological events in the retina and lateral geniculate body and to obtain psychophysical data for comparison with these studies. Spatial and temporal resolution and chromatic discrimination will be investigated. Evidence for lateral interaction in the retina and the nature of the organization of receptive fields in the nervous system have resulted in the development of a number of models concerning the relation of visual performance to physiological mechanisms. A major objective of this project is to obtain data necessary for the evaluation of hypotheses concerning the relation of visual function to physiological mechanisms.